US9542279B2 - Shadow paging based log segment directory - Google Patents

Shadow paging based log segment directory Download PDF

Info

Publication number
US9542279B2
US9542279B2 US13/290,726 US201113290726A US9542279B2 US 9542279 B2 US9542279 B2 US 9542279B2 US 201113290726 A US201113290726 A US 201113290726A US 9542279 B2 US9542279 B2 US 9542279B2
Authority
US
United States
Prior art keywords
log segment
log
page
pages
directory
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active, expires
Application number
US13/290,726
Other languages
English (en)
Other versions
US20130117241A1 (en
Inventor
Ivan Schreter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SAP SE
Original Assignee
SAP SE
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SAP SE filed Critical SAP SE
Priority to US13/290,726 priority Critical patent/US9542279B2/en
Assigned to SAP AG reassignment SAP AG ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SCHRETER, IVAN
Priority to EP12006157.7A priority patent/EP2590078B1/fr
Priority to CN201210433365.4A priority patent/CN103198088B/zh
Publication of US20130117241A1 publication Critical patent/US20130117241A1/en
Assigned to SAP SE reassignment SAP SE CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: SAP AG
Application granted granted Critical
Publication of US9542279B2 publication Critical patent/US9542279B2/en
Active legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F11/00—Error detection; Error correction; Monitoring
    • G06F11/07—Responding to the occurrence of a fault, e.g. fault tolerance
    • G06F11/14—Error detection or correction of the data by redundancy in operation
    • G06F11/1402—Saving, restoring, recovering or retrying
    • G06F11/1471—Saving, restoring, recovering or retrying involving logging of persistent data for recovery
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F16/00—Information retrieval; Database structures therefor; File system structures therefor
    • G06F16/20—Information retrieval; Database structures therefor; File system structures therefor of structured data, e.g. relational data
    • G06F16/23—Updating
    • G06F16/2358—Change logging, detection, and notification
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F16/00—Information retrieval; Database structures therefor; File system structures therefor
    • G06F16/20—Information retrieval; Database structures therefor; File system structures therefor of structured data, e.g. relational data
    • G06F16/23—Updating
    • G06F16/2379—Updates performed during online database operations; commit processing
    • G06F17/30368—
    • G06F17/30377—

Definitions

  • the subject matter described herein relates to techniques for providing a log segment directory utilizing shadow paging as part of a data storage application.
  • Databases use logging to store operations performed on corresponding data in a synchronous fashion to a log while, at the same time, writing data to a corresponding data area asynchronously. In cases of a crash or other data recovery event, the data area is recovered to a potentially older state. Replaying the log will bring the database to the last committed state.
  • Logged data is typically stored in fixed-size or variable-sized log segments which can be represented as operation system files on a corresponding disk. Each log segment can have associated metadata such as log sequence number of the first and last entries in the segment. The metadata can also include a current state of a log segment such as open, closed, backed-up of free.
  • replay of data transactions is initiated in a data storage application. Pages of a log segment directory characterizing metadata for a plurality of log segment are loaded into memory. Thereafter, redundant pages within the log segment directory are removed. It is then determined, based on the log segment directory, which log segments need to be accessed. These log segments are accessed to execute the log replay.
  • Metadata for each log segment can include one or more of: a log sequence number of a first entry and a last entry in the log segment, and a current state of the log segment.
  • the log segment directory can be divided into fixed-sized or varying sized pages.
  • Each page of the log segment directory can include one or more of: an index of a first log segment addressed by the page, a page generation value, and a checksum value, and a fixed number of log segment metadata.
  • Removal of the redundant pages within the log segment directory can include removing pages having a same index as another page and correct checksum value but with a lower page generation value.
  • a metadata entry for a particular log segment can be modified.
  • modification can include: modifying metadata of the log segment in memory, increasing a value for a current page generation counter, setting the page generation value for the log segment to the current generation counter value, assigning a new physical secondary storage location for a new page for the log segment to a physical secondary storage position taken from a free list data structure, computing a new checksum for the log segment, and adding a previous physical secondary storage location for an old page for the log segment to the free list data structure.
  • the metadata can be modified in response to a request to execute an operation selected from a group including, for example, closing a log segment, opening a new log segment, setting a log segment backup flag, and marking a log segment as free.
  • pages of a log segment directory are loaded into memory.
  • the log segment directory comprises metadata for a plurality of log segments such that each page of the log segment directory comprises an index of a first log segment addressed by the page, a page generation value, a checksum value and a fixed number of log segment metadata.
  • Metadata of a first log segment in memory is then modified.
  • a value for a current page generation counter is increased and the page generation value for the log segment is changed to the current generation counter value.
  • a new physical secondary storage location for a new page for the log segment is assigned to a physical secondary storage position taken from a free list data structure.
  • a checksum is computed for the log segment.
  • the previous physical secondary storage location for an old page for the log segment can be moved to the free list data structure.
  • Articles of manufacture are also described that comprise computer executable instructions permanently stored on non-transitory computer readable media, which, when executed by a computer, causes the computer to perform operations herein.
  • computer systems are also described that may include a processor and a memory coupled to the processor.
  • the memory may temporarily or permanently store one or more programs that cause the processor to perform one or more of the operations described herein.
  • operations specified by methods can be implemented by one or more data processors either within a single computing system or distributed among two or more computing systems.
  • log segment metadata is stored as a page at a well-defined position within the log segment (e.g., at the beginning of the log segment, etc.). Changes to the metadata such as state change requires the page to be accordingly modified.
  • all log segments first have to be scanned (at least partially) for metadata information which can slow down the data recovery process.
  • FIG. 1 is a diagram illustrating a system including a data storage application
  • FIG. 2 is a process flow diagram illustrating data recovery using a log segment directory
  • FIG. 3 is a diagram illustrating details of the system of FIG. 1 ;
  • FIG. 4 is a diagram illustrating the modification of log segment metadata in the log segment directory.
  • FIG. 1 shows an example of a system 100 in which a computing system 102 , which can include one or more programmable processors that can be collocated, linked over one or more networks, etc., executes one or more modules, software components, or the like of a data storage application 104 .
  • the data storage application 104 can include one or more of a database, an enterprise resource program, a distributed storage system (e.g. NetApp Filer available from NetApp of Sunnyvale, Calif.), or the like.
  • the one or more modules, software components, or the like can be accessible to local users of the computing system 102 as well as to remote users accessing the computing system 102 from one or more client machines 106 over a network connection 110 .
  • One or more user interface screens produced by the one or more first modules can be displayed to a user, either via a local display or via a display associated with one of the client machines 106 .
  • Data units of the data storage application 104 can be transiently stored in a persistence layer 112 (e.g. a page buffer or other type of temporary persistency layer), which can write the data, in the form of storage pages, to one or more storages 114 , for example via an input/output component 116 .
  • a persistence layer 112 e.g. a page buffer or other type of temporary persistency layer
  • the one or more storages 114 can include one or more physical storage media or devices (e.g. hard disk drives, persistent flash memory, random access memory, optical media, magnetic media, and the like) configured for writing data for longer term storage. It should be noted that the storage 114 and the input/output component 116 can be included in the computing system 102 despite their being shown as external to the computing system 102 in FIG. 1 .
  • physical storage media or devices e.g. hard disk drives, persistent flash memory, random access memory, optical media, magnetic media, and the like
  • Data retained at the longer term storage 114 can be organized in pages, each of which has allocated to it a defined amount of storage space.
  • the amount of storage space allocated to each page can be constant and fixed. However, other implementations in which the amount of storage space allocated to each page can vary are also within the scope of the current subject matter.
  • FIG. 2 is a process flow diagram 200 in which, at 210 , replay of data transactions in a data storage application are initiated.
  • pages of a log segment directory are loaded into memory.
  • the log segment directory comprises metadata characterizing a plurality of log segments. Redundant pages within the log segment directory are, at 230 , removed. Thereafter, it is determined based on the log segment directory, at 340 , which log segments need to be accessed so that, at 350 , the log segments can be accessed to enable the replay.
  • FIG. 3 shows a software architecture 300 consistent with one or more features of the current subject matter.
  • a data storage application 104 which can be implemented in one or more of hardware and software, can include one or more of a database application, a network-attached storage system, or the like. According to at least some implementations of the current subject matter, such a data storage application 104 can include or otherwise interface with a persistence layer 112 or other type of memory buffer, for example via a persistence interface 302 .
  • a page buffer 304 within the persistence layer 112 can store one or more logical pages 306 , and optionally can include shadow pages, active pages, and the like. The logical pages 306 retained in the persistence layer 112 can be written to a storage (e.g.
  • the storage 114 can include one or more data volumes 310 where stored pages 312 are allocated at physical memory blocks.
  • the data storage application 104 can include or be otherwise in communication with a page manager 314 and/or a savepoint manager 316 .
  • the page manager 314 can communicate with a page management module 320 at the persistence layer 112 that can include a free block manager 322 that monitors page status information 324 , for example the status of physical pages within the storage 114 and logical pages in the persistence layer 112 (and optionally in the page buffer 304 ).
  • the savepoint manager 316 can communicate with a savepoint coordinator 326 at the persistence layer 204 to handle savepoints, which are used to create a consistent persistent state of the database for restart after a possible crash.
  • the page management module of the persistence layer 112 can implement a shadow paging.
  • the free block manager 322 within the page management module 320 can maintain the status of physical pages.
  • the page buffer 304 can included a fixed page status buffer that operates as discussed herein.
  • a converter component 340 which can be part of or in communication with the page management module 320 , can be responsible for mapping between logical and physical pages written to the storage 114 .
  • the converter 340 can maintain the current mapping of logical pages to the corresponding physical pages in a converter table 342 .
  • the converter 340 can maintain a current mapping of logical pages 306 to the corresponding physical pages in one or more converter tables 342 .
  • the storage page to be loaded can be looked up from the one or more converter tables 342 using the converter 340 .
  • a logical page is written to storage 114 the first time after a savepoint, a new free physical page is assigned to the logical page.
  • the free block manager 322 marks the new physical page as “used” and the new mapping is stored in the one or more converter tables 342 .
  • the persistence layer 112 can ensure that changes made in the data storage application 104 are durable and that the data storage application 104 can be restored to a most recent committed state after a restart.
  • Writing data to the storage 114 need not be synchronized with the end of the writing transaction. As such, uncommitted changes can be written to disk and committed changes may not yet be written to disk when a writing transaction is finished. After a system crash, changes made by transactions that were not finished can be rolled back. Changes occurring by already committed transactions should not be lost in this process.
  • a logger component 344 can also be included to store the changes made to the data of the data storage application in a linear log. The logger component 344 can be used during recovery to replay operations since a last savepoint to ensure that all operations are applied to the data and that transactions with a logged “commit” record are committed before rolling back still-open transactions at the end of a recovery process.
  • writing data to a disk is not necessarily synchronized with the end of the writing transaction. Situations can occur in which uncommitted changes are written to disk and while, at the same time, committed changes are not yet written to disk when the writing transaction is finished. After a system crash, changes made by transactions that were not finished must be rolled back and changes by committed transaction must not be lost.
  • redo log information can be written by the logger component 344 whenever a change is made. This information can be written to disk at latest when the transaction ends. The log entries can be persisted in separate log volumes while normal data is written to data volumes. With a redo log, committed changes can be restored even if the corresponding data pages were not written to disk.
  • the persistence layer 112 can use a combination of undo log entries (from one or more logs) and shadow paging.
  • the persistence interface 302 can handle read and write requests of stores (e.g., in-memory stores, etc.).
  • the persistence interface 302 can also provide write methods for writing data both with logging and without logging. If the logged write operations are used, the persistence interface 302 invokes the logger 344 .
  • the logger 344 provides an interface that allows stores (e.g., in-memory stores, etc.) to directly add log entries into a log queue.
  • the logger interface also provides methods to request that log entries in the in-memory log queue are flushed to disk.
  • Log entries contain a log sequence number, the type of the log entry and the identifier of the transaction. Depending on the operation type additional information is logged by the logger 344 . For an entry of type “update”, for example, this would be the identification of the affected record and the after image of the modified data.
  • savepoints can be periodically performed that write all changes to disk that were made (e.g., in memory, etc.) since the last savepoint.
  • savepoints can be periodically performed that write all changes to disk that were made (e.g., in memory, etc.) since the last savepoint.
  • the logger 344 When the logger 344 is invoked for writing log entries, it does not immediately write to disk. Instead it can put the log entries into a log queue in memory. The entries in the log queue can be written to disk at the latest when the corresponding transaction is finished (committed or aborted). To guarantee that the committed changes are not lost, the commit operation is not successfully finished before the corresponding log entries are flushed to disk. Writing log queue entries to disk can also be triggered by other events, for example when log queue pages are full or when a savepoint is performed.
  • the logger 344 can write a database log (or simply referred to herein as a “log”) sequentially into a memory buffer in natural order (e.g., sequential order, etc.).
  • the database log can be segmented such that it includes a plurality of log segments.
  • the logger 344 can additionally generate and maintain a log segment directory.
  • the log segment directory can maintain metadata for each log segment in the log segment directory. This metadata can include, for example, a log sequence number of the first and last entry in this segment and data characterizing a current state of the log segment (e.g., open, closed, backed-up, free, etc.).
  • Each page can have a header containing the following information: (i) an index of first log segment addressed by this page (first metadata in the page corresponds to this log segment), which is naturally a multiple of metadata_per_page; (ii) a page generation value (which can be based on an increasing page generation counter); and (iii) a checksum value.
  • a metadata entry for the corresponding log segment needs to be modified and persisted.
  • an operation such as closing a log segment, opening a new log segment, setting log segment backup flag or marking a log segment as free
  • a metadata entry for the corresponding log segment needs to be modified and persisted.
  • the following operations are performed. First, at 410 , metadata of the log segment is modified. The current page generation counter is then incremented, at 420 and the page generation value for the log segment is set, at 430 , to the current page counter value. Subsequently, at 440 , a new physical secondary storage position for the modified page for the log segment is obtained from a free list data structure used for memory allocation. A new checksum is, at 450 , then computed for the log segment.
  • the modified page for the log segment is then, at 460 , written to the new physical secondary storage position (as obtained previously from the free list data structure).
  • the old physical secondary storage position for the previous version of the page for the log segment can be moved to the free list data structure.
  • aspects of the subject matter described herein can be embodied in systems, apparatus, methods, and/or articles depending on the desired configuration.
  • various implementations of the subject matter described herein can be realized in digital electronic circuitry, integrated circuitry, specially designed application specific integrated circuits (ASICs), computer hardware, firmware, software, and/or combinations thereof.
  • ASICs application specific integrated circuits
  • These various implementations can include implementation in one or more computer programs that are executable and/or interpretable on a programmable system including at least one programmable processor, which can be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.
  • machine-readable medium refers to any computer program product, apparatus and/or device, such as for example magnetic discs, optical disks, memory, and Programmable Logic Devices (PLDs), used to provide machine instructions and/or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal.
  • machine-readable signal refers to any signal used to provide machine instructions and/or data to a programmable processor.
  • the machine-readable medium can store such machine instructions non-transitorily, such as for example as would a non-transient solid state memory or a magnetic hard drive or any equivalent storage medium.
  • the machine-readable medium can alternatively or additionally store such machine instructions in a transient manner, such as for example as would a processor cache or other random access memory associated with one or more physical processor cores.
  • the subject matter described herein can be implemented in a computing system that includes a back-end component, such as for example one or more data servers, or that includes a middleware component, such as for example one or more application servers, or that includes a front-end component, such as for example one or more client computers having a graphical user interface or a Web browser through which a user can interact with an implementation of the subject matter described herein, or any combination of such back-end, middleware, or front-end components.
  • a client and server are generally, but not exclusively, remote from each other and typically interact through a communication network, although the components of the system can be interconnected by any form or medium of digital data communication.
  • Examples of communication networks include, but are not limited to, a local area network (“LAN”), a wide area network (“WAN”), and the Internet.
  • LAN local area network
  • WAN wide area network
  • Internet the Internet

Landscapes

  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Databases & Information Systems (AREA)
  • Data Mining & Analysis (AREA)
  • Quality & Reliability (AREA)
  • Information Retrieval, Db Structures And Fs Structures Therefor (AREA)
US13/290,726 2011-11-07 2011-11-07 Shadow paging based log segment directory Active 2032-02-28 US9542279B2 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US13/290,726 US9542279B2 (en) 2011-11-07 2011-11-07 Shadow paging based log segment directory
EP12006157.7A EP2590078B1 (fr) 2011-11-07 2012-08-30 Répertoire de segment de journal à base de pages dupliquées
CN201210433365.4A CN103198088B (zh) 2011-11-07 2012-09-28 基于阴影分页的日志段目录

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US13/290,726 US9542279B2 (en) 2011-11-07 2011-11-07 Shadow paging based log segment directory

Publications (2)

Publication Number Publication Date
US20130117241A1 US20130117241A1 (en) 2013-05-09
US9542279B2 true US9542279B2 (en) 2017-01-10

Family

ID=47008214

Family Applications (1)

Application Number Title Priority Date Filing Date
US13/290,726 Active 2032-02-28 US9542279B2 (en) 2011-11-07 2011-11-07 Shadow paging based log segment directory

Country Status (3)

Country Link
US (1) US9542279B2 (fr)
EP (1) EP2590078B1 (fr)
CN (1) CN103198088B (fr)

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8768891B2 (en) * 2012-04-27 2014-07-01 Sap Ag Ensuring database log recovery consistency
US9672237B2 (en) * 2013-03-15 2017-06-06 Amazon Technologies, Inc. System-wide checkpoint avoidance for distributed database systems
US9558216B2 (en) 2014-11-21 2017-01-31 Sap Se Moving tables across nodes in an in-memory database instance
US10177025B2 (en) 2016-07-28 2019-01-08 Asm Ip Holding B.V. Method and apparatus for filling a gap
US9887082B1 (en) 2016-07-28 2018-02-06 Asm Ip Holding B.V. Method and apparatus for filling a gap
US10395919B2 (en) 2016-07-28 2019-08-27 Asm Ip Holding B.V. Method and apparatus for filling a gap
CN106649615B (zh) * 2016-11-30 2020-09-22 苏州浪潮智能科技有限公司 一种日志段管理方法及装置
US9916980B1 (en) 2016-12-15 2018-03-13 Asm Ip Holding B.V. Method of forming a structure on a substrate
US10545952B2 (en) * 2017-01-31 2020-01-28 Xactly Corporation Multitenant architecture for prior period adjustment processing
CN108984566B (zh) * 2017-06-02 2022-01-28 伊姆西Ip控股有限责任公司 用于文件系统日志的方法和设备
US10990581B1 (en) * 2017-09-27 2021-04-27 Amazon Technologies, Inc. Tracking a size of a database change log
US10936441B2 (en) * 2017-12-15 2021-03-02 Microsoft Technology Licensing, Llc Write-ahead style logging in a persistent memory device

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6192365B1 (en) * 1995-07-20 2001-02-20 Novell, Inc. Transaction log management in a disconnectable computer and network
US20050182797A1 (en) * 2004-02-12 2005-08-18 International Business Machines Corporation Method and apparatus for file system snapshot persistence
US20060224636A1 (en) 2005-04-05 2006-10-05 Microsoft Corporation Page recovery using volume snapshots and logs
US20080046429A1 (en) * 2006-08-16 2008-02-21 Yahoo! Inc. System and method for hierarchical segmentation of websites by topic
US20100082547A1 (en) * 2008-09-22 2010-04-01 Riverbed Technology, Inc. Log Structured Content Addressable Deduplicating Storage
US20110251997A1 (en) * 2010-04-12 2011-10-13 Microsoft Corporation Logical replication in clustered database system with adaptive cloning
US8489656B2 (en) * 2010-05-28 2013-07-16 Commvault Systems, Inc. Systems and methods for performing data replication

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101251814B (zh) * 2008-02-04 2010-04-07 浙江大学 一种在操作系统中实现可信恢复系统的方法
CN101866305B (zh) * 2010-05-21 2013-03-06 武汉大学 支持数据查询和快速恢复的连续数据保护方法及系统

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6192365B1 (en) * 1995-07-20 2001-02-20 Novell, Inc. Transaction log management in a disconnectable computer and network
US20050182797A1 (en) * 2004-02-12 2005-08-18 International Business Machines Corporation Method and apparatus for file system snapshot persistence
US20060224636A1 (en) 2005-04-05 2006-10-05 Microsoft Corporation Page recovery using volume snapshots and logs
US20080046429A1 (en) * 2006-08-16 2008-02-21 Yahoo! Inc. System and method for hierarchical segmentation of websites by topic
US20100082529A1 (en) * 2008-05-08 2010-04-01 Riverbed Technology, Inc. Log Structured Content Addressable Deduplicating Storage
US20100082547A1 (en) * 2008-09-22 2010-04-01 Riverbed Technology, Inc. Log Structured Content Addressable Deduplicating Storage
US20110251997A1 (en) * 2010-04-12 2011-10-13 Microsoft Corporation Logical replication in clustered database system with adaptive cloning
US8489656B2 (en) * 2010-05-28 2013-07-16 Commvault Systems, Inc. Systems and methods for performing data replication

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Chin-Hsien, Wu et al. "The Design of Efficient Initialization and Crash Recovery for Log-based File Systems Over Flash Memory". ACM Transactions on Storage. vol. 2. No. 4. (Nov. 1, 2006):449-467.

Also Published As

Publication number Publication date
US20130117241A1 (en) 2013-05-09
CN103198088A (zh) 2013-07-10
EP2590078B1 (fr) 2016-01-20
EP2590078A3 (fr) 2014-08-27
EP2590078A2 (fr) 2013-05-08
CN103198088B (zh) 2017-07-25

Similar Documents

Publication Publication Date Title
US9542279B2 (en) Shadow paging based log segment directory
US9483512B2 (en) Columnar database using virtual file data objects
US9092475B2 (en) Database log parallelization
US10146643B2 (en) Database recovery and index rebuilds
US8768891B2 (en) Ensuring database log recovery consistency
US8949190B2 (en) Point-in-time database recovery using log holes
US9069704B2 (en) Database log replay parallelization
US9058371B2 (en) Distributed database log recovery
US9208191B2 (en) Lock-free, scalable read access to shared data structures
US10949415B2 (en) Logging system using persistent memory
US9183245B2 (en) Implicit group commit when writing database log entries
US20150242451A1 (en) Database Table Re-Partitioning Using Two Active Partition Specifications
US20110060724A1 (en) Distributed database recovery
US20130159339A1 (en) Data Container Access in a Database System
US11176004B2 (en) Test continuous log replay
GB2516872A (en) A method for a logging process in a data storage system
US10452496B2 (en) System and method for managing storage transaction requests
US10372688B2 (en) Moving data within a distributed data storage system using virtual file links
US9575990B2 (en) Partitioning data within a distributed data storage system using virtual file links
US20120246414A1 (en) Lock-free release of shadow pages in a data storage application
US20140149697A1 (en) Memory Pre-Allocation For Cleanup and Rollback Operations
US8694796B2 (en) Secure data deletion in a database
US8615632B2 (en) Co-storage of data storage page linkage, size, and mapping

Legal Events

Date Code Title Description
AS Assignment

Owner name: SAP AG, GERMANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SCHRETER, IVAN;REEL/FRAME:027455/0052

Effective date: 20111107

AS Assignment

Owner name: SAP SE, GERMANY

Free format text: CHANGE OF NAME;ASSIGNOR:SAP AG;REEL/FRAME:033625/0223

Effective date: 20140707

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

STCF Information on status: patent grant

Free format text: PATENTED CASE

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1551); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Year of fee payment: 4